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Act now to track health effects of nuclear crisis

By Debora MacKenzie

Radiation biologists say they must organise now to monitor any illness caused by fallout from the stricken nuclear plant in Fukushima, Japan. They warn that failure to do this after the 1986 Chernobyl accident in Ukraine has left conflicting claims circulating ever since.

The lesson of Chernobyl, they say, is that even if the Fukushima crisis has negligible effects on health, disbelief and speculation will do their own damage if people are not credibly informed.

The medical effect of a sievert or more of radiation is severe, but well understood, and unlikely outside the plant itself. Much less is known, however, about what will happen to the thousands of people who now seem likely to be exposed to millisieverts of the volatile isotopes iodine-131 and caesium-137, carried by steam or smoke from damaged fuel and deposited on surfaces or food. On Tuesday Japan’s science ministry reported that elevated levels of both isotopes have been measured 40 kilometres from the nuclear plant.

Health researchers are deeply divided over the effects of such low doses, says Elizabeth Cardis of the Centre for Research in Environmental Epidemiology in Barcelona, Spain, a former head of radiation at the International Agency for Research on Cancer. This is partly because studies after Chernobyl were fragmented and contradictory, and did not begin until years after the accident.

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Wild speculation

The exposure of children to the iodine from Chernobyl is known to have caused some 6000 cases of thyroid cancer so far. Cardis has calculated that radiation from the Ukrainian reactor could cause 25,000 extra cases of other cancers across Europe by 2065. The United Nations has sponsored an investigation, however, which reported in February that it had found “no persuasive evidence” for this.

Disagreements such as these are partly why statements about the health effects of radiation are widely disbelieved, says Keith Baverstock of the University of Eastern Finland in Kuopio, formerly head of radiation protection at the World Health Organization’s European office. He says the uncertainty causes Chernobyl survivors great psychological stress. In February he, Cardis and other radiation researchers called for a long-term fund to study Chernobyl’s effects, in part to end “the present wild speculation”.

Japan might avoid these problems. “People should plan a research strategy as soon as the plants are safe,” says Baverstock. The effects of doses on the order of 100 millisieverts should be traceable, says Cardis, if researchers map radiation and set up registries of people, then get legal permission to use local health data to follow cancer incidence for the coming decades.

That was how the Radiation Effects Research Foundation in Hiroshima, Japan, found elevated leukaemia rates among survivors of the 1945 nuclear bomb attack on the city. “They have the best radiation epidemiologists in the world,” says Cardis, and could allay much anxiety by doing publicly credible investigations of the effects of the Fukushima fallout.